package org.penguin.study.bk.base.util;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * @author chengyinghua
 */
public class MD5Util {

	public static String byteArrayToHexString(byte b[]) {
		StringBuffer resultSb = new StringBuffer();
		for (int i = 0; i < b.length; i++){
			resultSb.append(byteToHexString(b[i]));
		}
		return resultSb.toString();
	}

	private static String byteToHexString(byte b) {
		int n = b;
		if (n < 0) {
			n += 256;
		}
		int d1 = n / 16;
		int d2 = n % 16;
		return hexDigits[d1] + hexDigits[d2];
	}

	public static String MD5Encode(String origin, String charsetname) {
		String resultString = null;
		try {
			resultString = new String(origin);
			MessageDigest md = MessageDigest.getInstance("MD5");
			if (charsetname == null || "".equals(charsetname)) {
				resultString = byteArrayToHexString(md.digest(resultString.getBytes()));
			} else {
				resultString = byteArrayToHexString(md.digest(resultString.getBytes(charsetname)));
			}
		} catch (Exception exception) {
		}
		return resultString;
	}

	public static String MD5Encode16(String origin, String charsetname) {
		String resultString = null;
		try {
			resultString = MD5Encode(origin,charsetname).substring(8, 24);
		} catch (Exception exception) {
		}
		return resultString;
	}

	private static final String hexDigits[] = { "0", "1", "2", "3", "4", "5",
			"6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };

	public static String getMD5Str(String str) {
		MessageDigest messageDigest = null;

		try {
			messageDigest = MessageDigest.getInstance("MD5");
			messageDigest.reset();
			messageDigest.update(str.getBytes("UTF-8"));
		} catch (NoSuchAlgorithmException var5) {
		} catch (UnsupportedEncodingException var6) {
		}

		byte[] byteArray = messageDigest.digest();
		StringBuffer md5StrBuff = new StringBuffer();

		for(int i = 0; i < byteArray.length; ++i) {
			if (Integer.toHexString(255 & byteArray[i]).length() == 1) {
				md5StrBuff.append("0").append(Integer.toHexString(255 & byteArray[i]));
			} else {
				md5StrBuff.append(Integer.toHexString(255 & byteArray[i]));
			}
		}

		return md5StrBuff.toString();
	}
}
